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(: Test: K2-FilterExpr-8                                 :)
(: Written by: Frans Englich                             :)
(: Date: 2007-11-22T11:31:21+01:00                       :)
(: Purpose: Use self::processing-instruction() in a filter predicate, combined with a treat as. :)
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(<?z?>, <?y?>)[self::processing-instruction(y)] treat as empty-sequence()